DaveSSS 

I go up a 10-12% grade regularly and use the lowest gear ratio that's readily available for my sram force axs 12 speed drivetrain. With all sram parts, they offer a 43/30 crank and 10-36 cassette. A 30/36 ratio works great at speeds in the 4-5 mph range. I don't want to give up top gearing, so I use Shimano grx cranks - either a 48/31 or 46/30. I only weigh 135, but I'm 68 years old now and don't have the power I used too. I do a fair amount of pedaling standing and I can do this same steep climb pedaling standing, but my 31/28 ratio is a bit too low and the 31/24 only allows a cadence around 50, which seems like a grind, so I prefer to sit through this climb. My replaced knees probably appreciate it too. I ride out of the saddle in the big ring, quite a bit on lesser slopes. I regularly ride a 52 mile loop from Loveland to Estes Park - sometimes through Glen Haven and sometimes not. The Glen Haven route has the steep climb.

Today I took a different route with a 4.5 mile climb that has several 10% sections, but nothing exceeding 10%. I was able to ride those sections standing in my 31/24 or sitting in my 31/32 and never used my 36T sprocket. I have gained some strength in the 3rd year of my comeback to cycling, but you can't always keep ahead of old age. As some point, I'll quit improving and start the downhill slide again. I certainly won't get rid of the 36T sprocket.

On of my biggest complaints about SRAM's drivetrain offerings is the 13T difference on every crankset. Just not enough range. That's why I've never used a SRAM crank.

Calsun

The lowest gear I have ever used is 45/28 and the 28 replaced a stock 26 tooth cog as I wanted an ultra low gear going over the sierras with a 15 lb load of touring gear on the bike. The cog dished and I finished the trip with 45/24 gears on the grades. That was in the days when "racing" bikes had 45/52 chainrings at the front and only mountain bikes or special world touring bike had smaller chainrings. Now it is common to equip racing bikes with 36/32 gears which is very very low.

Stock bikes often have less than optimum gears for the people who ride them and more bike shops should recommend changing them for their customers.

terrymorse 

45x28 is a big climbing gear by today's standards. It must have required some very low cadences and standing over the Sierra passes.

bikecalc.com

Sonora Pass has sections in excess of 20%.


Sonora Pass Rd, near Hwy 395

That 26% section:

Eric F 

Oh, hell no.